Many ATMs are located in an unattended environment. As a result, the ATM must be able to ensure that it remains in operation without any intervention from a user of the ATM. Any hardware or software problems may cause the ATM to require a visit from an ATM technician to restore such an ATM to normal operation. These ATM technician visits are expensive for the ATM owner and introduce an extended time period during which the ATM cannot be used by ATM customers desiring to execute transactions at that ATM. ATM technician visits are therefore expensive and undesirable.
One recurring cause of ATM failure is jamming of receipt paper resulting from a customer blocking a receipt exit aperture (also called a slot) with his/her finger while waiting for a receipt to be dispensed. Although this problem may appear to be trivial, it is very expensive and time consuming to resolve.